Abstract: most of what has been written about ancient technical knowledge relies on written sources, which reflect the views of only a small portion of the repositories of the technical knowledge in question, i.e. the 'top' level of well-educated, relatively wealthy technicians. But what about 'invisible' technicians? This paper is an attempt to retrieve information about them by looking at funerary evidence. I will focus on tombs from the first to second century AD that bear the image of the carpenter's square, and explore what they can tell us about how the technicians viewed themselves and their activities.